1. Perimeter and Area January 24, 2011

2. Perimeter Example 1Find the Perimeter a. a square with a side length of 10 inches10 in. P = 4sPerimeter formula = 4(10)Replace s with 10. = 40Multiply. The perimeter is 40 inches. 10 in.

3. b.a rectangle with a length of 13 centimeters and a width of 4 centimeters P = 2( + w) = 2(13 + 4) = 13, w = 4 = 2(17)Add. = 34Multiply. The perimeter is 34 centimeters. 13 cm 4 cm

4. P = a + b + cPerimeter formula = 11 + 7 + 12a = 11, b = 7, c = 12 = 30Add. The perimeter of the triangle is 30 meters. 11 m 12 m 7 m

5. 25 yd 18 yd P = 2(a + b) Perimeter formula = 2(18 + 25)a = 18, b = 25 = 2(43)Add. = 86Multiply. The perimeter of the parallelogram is 86 yards.

6. Find the circumference of each circle to the nearest tenth. a. The radius is 5 inches. C = 2  r Circumference formula = 2  (5)Replace r with 5. = 10  Simplify. The exact circumference is 10  feet. 10  ENTER 31.41592654 The circumference is about 31.4 inches.

7. b. The diameter is 22 meters. C =  d Circumference formula =  (22)Replace d with 22. = 22  Simplify.  69.1 Use a calculator to evaluate 22 . The circumference is about 69.1 meters.

8. Area a. a square that has a side length of 9 inches A = s²Area formula = 9²s = 9 = 81Multiply. The area is 81 square inches.

9. b. a rectangle that has a length of 11 millimeters and a width of 4 millimeters A = wArea formula = 11(4) = 11, w = 4 = 44Multiply. The area of the rectangle is 44 square millimeters.

10. a. a parallelogram that has a base of 30 feet and a height of 24 feet A = bhArea formula = 30(24)b = 30, h = 24 = 720Multiply. The area is 720 square feet. 24 ft 30 ft

11. a triangle that has a base of 13 kilometers and a height of 8 kilometers 8 km 13 km A = bhArea formula = (13)(8)b = 13, h = 8 = 52Multiply. The area is 52 square kilometers.

12. . The radius is 4 miles. A =  r²Area formula =  (4) ²Replace r with 4. = 16  Simplify.  50.3Use a calculator to evaluate 16 . The area is about 50.3 square miles. 4 mi

13. b. The diameter is 35 centimeters. A =  r²Area formula =  (17.5) ²Replace r with 17.5. = 306.25  Simplify.  962.1Use a calculator to evaluate 306.25 . 35 cm